The Role of Nutrition in Immune Health

The Role of Nutrition in Immune Health

Adequate and appropriate nutrition is required for all cells to function optimally and this includes the cells in the immune system.

An “activated” immune system further increases the demand for energy during periods of infection, with greater basal energy expenditure during fever for example. Thus, optimal nutrition for the best immunological outcomes supports the functions of immune cells allowing them to initiate effective responses against pathogens but also to resolve the response rapidly when necessary and to avoid any underlying chronic inflammation.

Immune function overall depends on a set of key nutrients, especially vitamin A,[1] C,[2] zinc[3] and iron,[4] for their role in white blood cell proliferation, immune cell differentiation and antioxidant activity. Therefore, low intake or deficiency in those nutrients may lead to low immunity,[5] and potentially low white blood cell (WBC) count or low immunoglobulin A (sIgA).

Age, Health Status, and Immune Defense

Specific populations may be more susceptible to immune dysfunction, such as children and the elderly.

Children are prone to deficiencies of iron and vitamin D, resulting in longer infection duration.[6] The elderly are at increased risk due to low water intake (e.g. in the case of urinary tract infections), malnourishment (e.g. poor appetite, digestive issues, difficulty eating) and the long-term effects of chronic disease (e.g. heart, disease, IBD, diabetes). The elderly are also at increased risk because of low sunlight exposure, vaccination,[7] age-related decline in renal function[8] and the decline in estrogen levels after menopause.[9]

Poor digestion, dysbiosis (parasitic infections), and impaired absorption may all reduce nutrient status, even if dietary levels are optimal. Poor fat digestion (gallbladder removal, gallstones, etc.) may particularly affect levels of the vital fat-soluble nutrients like essential fats or vitamins A and D.[10]

The Role of Antioxidants

The body also possesses antioxidant enzymes, which act in collaboration with the three defense mechanisms. The principal antioxidant enzymes are superoxide dismutase, catalase, and glutathione.

Dietary antioxidants work alongside these antioxidant enzymes to support neutralization of excessive Reactive Oxygen Species (ROS) formation. ROS are generated from exposure to environmental factors (e.g. cigarette smoke, alcohol, or poor diet) and our own metabolism (e.g. detoxification and fighting an infection). ROS induce oxidative stress leading to cell damage that can culminate in cell death.

Oxidative stress (free radical) damage is linked to the formation of many degenerative diseases, including cancer, cardiovascular disease, cataracts, and aging. By helping to prevent oxidative damage, of DNA[11][12] and cell membranes[13] for instance, dietary antioxidants help to conserve the integrity and function of cells and tissues, including those of the immune system.

Antioxidants Against Free Radicals

Fruits and vegetables are the healthiest and most beneficial source of antioxidants, including Beta-carotene, vitamin C, vitamin E, and selenium. Many of these compounds scavenge reactive oxygen species, including free radicals, which increase oxidative stress and have been associated with aging, CHD, diabetes, cancer, arthritis, and other chronic diseases as well as Alzheimer’s and Parkinson’s disease.[54][55][56][57][58][59][60][61]

Think of Interactions as a Whole

Chronic disease determinants or anthropogens (anthropogenic effects, processes, objects, or materials derived from human activities), have varying levels of potency depending on a range of factors such as genes, environment, and exposure.

Although each may impact independently in the development of chronic disease, findings have suggested it is more realistic to think of interactions as a whole or integral process taking place in a living organism, both within and between determinant factors, instead of a simple linear approach.[62]

Just like isolating nutrients from foods ignores the interactive relationship of nutrients found in whole meal patterns considering inactivity, sleep, or social factors in the absence of nutrition provides only part of the etiological answer to disease manifestation.

The interactions between determinants may be hidden below the surface, like an iceberg, but is a most important aspect of a modern Lifestyle Medicine approach to diseases and conditions.[63]

[14] Campbell, T C. “The Past, Present, and Future of Nutrition and Cancer: Part 1-Was A Nutritional Association Acknowledged a Century Ago?” Nutrition and Cancer., U.S. National Library of Medicine, July 2017, www.ncbi.nlm.nih.gov/pubmed/28594590.

[30] Report of the Dietary Guidelines Advisory Committee on the dietary guidelines for Americans, 2010: to the Secretary of Agriculture and the Secretary of Health and Human Services. Washington, DC: Agriculture Research Service, US Department of Agriculture, US Department of Health and Human Services; 2010.

[35] Report of the Dietary Guidelines Advisory Committee on the dietary guidelines for Americans, 2010: to the Secretary of Agriculture and the Secretary of Health and Human Services. Washington, DC: Agriculture Research Service, US Department of Agriculture, US Department of Health and Human Services; 2010.

[43] Freeman, A M, et al. “Trending Cardiovascular Nutrition Controversies.” Journal of the American College of Cardiology., U.S. National Library of Medicine, 7 Mar. 2017, www.ncbi.nlm.nih.gov/pubmed/28254181.

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Naked Food is an independent, nonpartisan, nonreligious, and nonbiased publication that reports evidence-based content pertaining to human and planetary health. We perform independent journalistic research on the variety of subjects that we report and we do not base our statements in mainstream sources.

Naked Food is published and sponsored by WFPB.ORG, a 501(c)3 non-profit organization that empowers sustainable health for humans and planet through a plant-based and sustainable lifestyle.

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